No harsh chemicals, no artificial smells and clean, clean laundry. Soap nuts are very cheap. For my household (of two) 1kg of soap nuts will last a year. That is doing approximately five loads of laundry a week. 1kg cost me €16.
How to use
For laundry use about 7 soap nuts per load. I also use a Magneto Ball because I live in a hard water area. The type I buy comes with a linen bag to put the soap nuts into. Place them on top of your laundry and run your cycle on cold. You can use hot but the soap nuts won't last as long apparently. I find cold works very well.
Occasionally I will run laundry through twice if I feel it isn't clean but that probably was because I needed to change the soap nuts.
For white clothing I spray with hydrogen peroxide before putting them in the wash.